[PATCHv4 02/12] arm64: Handle section maps for swapper/idmap
From: Suzuki K. Poulose
Date: Fri Oct 16 2015 - 13:09:34 EST
We use section maps with 4K page size to create the swapper/idmaps.
So far we have used !64K or 4K checks to handle the case where we
use the section maps.
This patch adds a new symbol, ARM64_SWAPPER_USES_SECTION_MAPS, to
handle cases where we use section maps, instead of using the page size
symbols.
Cc: Catalin Marinas <catalin.marinas@xxxxxxx>
Cc: Will Deacon <will.deacon@xxxxxxx>
Signed-off-by: Suzuki K. Poulose <suzuki.poulose@xxxxxxx>
Reviewed-by: Ard Biesheuvel <ard.biesheuvel@xxxxxxxxxx>
Acked-by: Mark Rutland <mark.rutland@xxxxxxx>
---
arch/arm64/include/asm/kernel-pgtable.h | 37 +++++++++++-----
arch/arm64/mm/mmu.c | 74 ++++++++++++++-----------------
2 files changed, 59 insertions(+), 52 deletions(-)
diff --git a/arch/arm64/include/asm/kernel-pgtable.h b/arch/arm64/include/asm/kernel-pgtable.h
index 3c92fa7..4e08faa 100644
--- a/arch/arm64/include/asm/kernel-pgtable.h
+++ b/arch/arm64/include/asm/kernel-pgtable.h
@@ -19,6 +19,19 @@
#ifndef __ASM_KERNEL_PGTABLE_H
#define __ASM_KERNEL_PGTABLE_H
+
+/*
+ * The linear mapping and the start of memory are both 2M aligned (per
+ * the arm64 booting.txt requirements). Hence we can use section mapping
+ * with 4K (section size = 2M) but not with 16K (section size = 32M) or
+ * 64K (section size = 512M).
+ */
+#ifdef CONFIG_ARM64_4K_PAGES
+#define ARM64_SWAPPER_USES_SECTION_MAPS 1
+#else
+#define ARM64_SWAPPER_USES_SECTION_MAPS 0
+#endif
+
/*
* The idmap and swapper page tables need some space reserved in the kernel
* image. Both require pgd, pud (4 levels only) and pmd tables to (section)
@@ -28,26 +41,28 @@
* could be increased on the fly if system RAM is out of reach for the default
* VA range, so 3 pages are reserved in all cases.
*/
-#ifdef CONFIG_ARM64_64K_PAGES
-#define SWAPPER_PGTABLE_LEVELS (CONFIG_PGTABLE_LEVELS)
-#else
+#if ARM64_SWAPPER_USES_SECTION_MAPS
#define SWAPPER_PGTABLE_LEVELS (CONFIG_PGTABLE_LEVELS - 1)
+#else
+#define SWAPPER_PGTABLE_LEVELS (CONFIG_PGTABLE_LEVELS)
#endif
#define SWAPPER_DIR_SIZE (SWAPPER_PGTABLE_LEVELS * PAGE_SIZE)
#define IDMAP_DIR_SIZE (3 * PAGE_SIZE)
/* Initial memory map size */
-#ifdef CONFIG_ARM64_64K_PAGES
-#define SWAPPER_BLOCK_SHIFT PAGE_SHIFT
-#define SWAPPER_BLOCK_SIZE PAGE_SIZE
-#define SWAPPER_TABLE_SHIFT PMD_SHIFT
-#else
+#if ARM64_SWAPPER_USES_SECTION_MAPS
#define SWAPPER_BLOCK_SHIFT SECTION_SHIFT
#define SWAPPER_BLOCK_SIZE SECTION_SIZE
#define SWAPPER_TABLE_SHIFT PUD_SHIFT
+#else
+#define SWAPPER_BLOCK_SHIFT PAGE_SHIFT
+#define SWAPPER_BLOCK_SIZE PAGE_SIZE
+#define SWAPPER_TABLE_SHIFT PMD_SHIFT
#endif
+/* The size of the initial kernel direct mapping */
+#define SWAPPER_INIT_MAP_SIZE (_AC(1, UL) << SWAPPER_TABLE_SHIFT)
/*
* Initial memory map attributes.
@@ -55,10 +70,10 @@
#define SWAPPER_PTE_FLAGS (PTE_TYPE_PAGE | PTE_AF | PTE_SHARED)
#define SWAPPER_PMD_FLAGS (PMD_TYPE_SECT | PMD_SECT_AF | PMD_SECT_S)
-#ifdef CONFIG_ARM64_64K_PAGES
-#define SWAPPER_MM_MMUFLAGS (PTE_ATTRINDX(MT_NORMAL) | SWAPPER_PTE_FLAGS)
-#else
+#if ARM64_SWAPPER_USES_SECTION_MAPS
#define SWAPPER_MM_MMUFLAGS (PMD_ATTRINDX(MT_NORMAL) | SWAPPER_PMD_FLAGS)
+#else
+#define SWAPPER_MM_MMUFLAGS (PTE_ATTRINDX(MT_NORMAL) | SWAPPER_PTE_FLAGS)
#endif
diff --git a/arch/arm64/mm/mmu.c b/arch/arm64/mm/mmu.c
index eed6d52..c2fa6b5 100644
--- a/arch/arm64/mm/mmu.c
+++ b/arch/arm64/mm/mmu.c
@@ -32,6 +32,7 @@
#include <asm/cputype.h>
#include <asm/fixmap.h>
+#include <asm/kernel-pgtable.h>
#include <asm/sections.h>
#include <asm/setup.h>
#include <asm/sizes.h>
@@ -406,14 +407,11 @@ static void __init map_mem(void)
* memory addressable from the initial direct kernel mapping.
*
* The initial direct kernel mapping, located at swapper_pg_dir, gives
- * us PUD_SIZE (4K pages) or PMD_SIZE (64K pages) memory starting from
- * PHYS_OFFSET (which must be aligned to 2MB as per
- * Documentation/arm64/booting.txt).
+ * us PUD_SIZE (with SECTION maps) or PMD_SIZE (without SECTION maps,
+ * memory starting from PHYS_OFFSET (which must be aligned to 2MB as
+ * per Documentation/arm64/booting.txt).
*/
- if (IS_ENABLED(CONFIG_ARM64_64K_PAGES))
- limit = PHYS_OFFSET + PMD_SIZE;
- else
- limit = PHYS_OFFSET + PUD_SIZE;
+ limit = PHYS_OFFSET + SWAPPER_INIT_MAP_SIZE;
memblock_set_current_limit(limit);
/* map all the memory banks */
@@ -424,21 +422,24 @@ static void __init map_mem(void)
if (start >= end)
break;
-#ifndef CONFIG_ARM64_64K_PAGES
- /*
- * For the first memory bank align the start address and
- * current memblock limit to prevent create_mapping() from
- * allocating pte page tables from unmapped memory.
- * When 64K pages are enabled, the pte page table for the
- * first PGDIR_SIZE is already present in swapper_pg_dir.
- */
- if (start < limit)
- start = ALIGN(start, PMD_SIZE);
- if (end < limit) {
- limit = end & PMD_MASK;
- memblock_set_current_limit(limit);
+ if (ARM64_SWAPPER_USES_SECTION_MAPS) {
+ /*
+ * For the first memory bank align the start address and
+ * current memblock limit to prevent create_mapping() from
+ * allocating pte page tables from unmapped memory. With
+ * the section maps, if the first block doesn't end on section
+ * size boundary, create_mapping() will try to allocate a pte
+ * page, which may be returned from an unmapped area.
+ * When section maps are not used, the pte page table for the
+ * current limit is already present in swapper_pg_dir.
+ */
+ if (start < limit)
+ start = ALIGN(start, SECTION_SIZE);
+ if (end < limit) {
+ limit = end & SECTION_MASK;
+ memblock_set_current_limit(limit);
+ }
}
-#endif
__map_memblock(start, end);
}
@@ -551,12 +552,12 @@ int kern_addr_valid(unsigned long addr)
return pfn_valid(pte_pfn(*pte));
}
#ifdef CONFIG_SPARSEMEM_VMEMMAP
-#ifdef CONFIG_ARM64_64K_PAGES
+#if !ARM64_SWAPPER_USES_SECTION_MAPS
int __meminit vmemmap_populate(unsigned long start, unsigned long end, int node)
{
return vmemmap_populate_basepages(start, end, node);
}
-#else /* !CONFIG_ARM64_64K_PAGES */
+#else /* !ARM64_SWAPPER_USES_SECTION_MAPS */
int __meminit vmemmap_populate(unsigned long start, unsigned long end, int node)
{
unsigned long addr = start;
@@ -691,7 +692,7 @@ void *__init fixmap_remap_fdt(phys_addr_t dt_phys)
{
const u64 dt_virt_base = __fix_to_virt(FIX_FDT);
pgprot_t prot = PAGE_KERNEL | PTE_RDONLY;
- int granularity, size, offset;
+ int size, offset;
void *dt_virt;
/*
@@ -717,24 +718,15 @@ void *__init fixmap_remap_fdt(phys_addr_t dt_phys)
*/
BUILD_BUG_ON(dt_virt_base % SZ_2M);
- if (IS_ENABLED(CONFIG_ARM64_64K_PAGES)) {
- BUILD_BUG_ON(__fix_to_virt(FIX_FDT_END) >> PMD_SHIFT !=
- __fix_to_virt(FIX_BTMAP_BEGIN) >> PMD_SHIFT);
-
- granularity = PAGE_SIZE;
- } else {
- BUILD_BUG_ON(__fix_to_virt(FIX_FDT_END) >> PUD_SHIFT !=
- __fix_to_virt(FIX_BTMAP_BEGIN) >> PUD_SHIFT);
-
- granularity = PMD_SIZE;
- }
+ BUILD_BUG_ON(__fix_to_virt(FIX_FDT_END) >> SWAPPER_TABLE_SHIFT !=
+ __fix_to_virt(FIX_BTMAP_BEGIN) >> SWAPPER_TABLE_SHIFT);
- offset = dt_phys % granularity;
+ offset = dt_phys % SWAPPER_BLOCK_SIZE;
dt_virt = (void *)dt_virt_base + offset;
/* map the first chunk so we can read the size from the header */
- create_mapping(round_down(dt_phys, granularity), dt_virt_base,
- granularity, prot);
+ create_mapping(round_down(dt_phys, SWAPPER_BLOCK_SIZE), dt_virt_base,
+ SWAPPER_BLOCK_SIZE, prot);
if (fdt_check_header(dt_virt) != 0)
return NULL;
@@ -743,9 +735,9 @@ void *__init fixmap_remap_fdt(phys_addr_t dt_phys)
if (size > MAX_FDT_SIZE)
return NULL;
- if (offset + size > granularity)
- create_mapping(round_down(dt_phys, granularity), dt_virt_base,
- round_up(offset + size, granularity), prot);
+ if (offset + size > SWAPPER_BLOCK_SIZE)
+ create_mapping(round_down(dt_phys, SWAPPER_BLOCK_SIZE), dt_virt_base,
+ round_up(offset + size, SWAPPER_BLOCK_SIZE), prot);
memblock_reserve(dt_phys, size);
--
1.7.9.5
--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at http://vger.kernel.org/majordomo-info.html
Please read the FAQ at http://www.tux.org/lkml/